Not Applicable.
Not Applicable.
The present invention relates generally to radar reflectors, and more particularly to a lightweight radar reflector comprising a plurality of conterminous corner reflectors, wherein the radar reflector is adjustably supported and positioned within an inflatable structure when the inflatable structure is inflated with air, gas or lighter-than-air gas.
In the past, corner radar reflectors, which typically consist of three planar surfaces suitable for reflecting radio frequency waves and connected together at right angles to each other, have been utilized for a number of military and commercial purposes. When radio frequency waves, emitted towards the radar reflector within a range of angles relative to the reflector center, strike the reflector they reflect directly back toward the source of emission. Consequently, a radar transceiver receiving such reflected radio frequency waves will indicate that the radar cross-section of the detected radar reflector is much bigger than the reflector actually is. Because of this feature, namely the ability to indicate a large radar cross-section relative to actual size, corner-type radar reflectors find particular applicability in military and industrial uses as floating and aerial radar decoys and beacons.
Disposing a collapsible radar reflector within an inflatable structure is particularly efficacious because the combined apparatus may be folded or otherwise compacted for storage using a minimum of storage space. Past radar reflectors have been constructed of lightweight materials to improve ease of handling and storage, and to enable the apparatus to float in the atmosphere when inflated with lighter-than-gas. In operation, such radar reflector apparatus are typically inflated with air, gas or a combination thereof so that as the inflatable structure inflates it imparts force to the radar reflector disposed therein in a manner to position the radar reflector to reflect radar waves when the inflatable structure is fully inflated. The inflatable structure may then, depending upon relative weight of the gas it is inflated with, be employed as an aerial or surface radar decoy or beacon. In the past, such decoys or beacons have typically been deployed as aerial radar beacons floating above terrain, or floating on the surface of the sea as ship radar decoys.
Past apparatus having an inflatable structure with a radar reflector disposed therein have, however, suffered from several disadvantages. For instance, when in use the effect of wind and other environmental forces upon the outer surface of the inflatable structure often imparts torsional and other forces to the radar reflector disposed within such that the shape of the radar reflector is thereby distorted. The ability of the radar reflector to optimally reflect radar waves is substantially degraded. Therefore, past apparatus lack the ability to effectively isolate the radar reflector supported within the inflatable structure from the effect of environmental forces imparted to the outer surface of the inflatable structure.
Another disadvantage of past inflatable structures with a radar reflector disposed therein has been that the radar reflector is affixed to the inflatable structure by a process that requires puncturing the surfaces of the inflatable structure. Such a process of affixation is detrimental to the structural integrity of the inflatable structure, and encourages leakage when the inflatable structure is inflated with air or gas. When the air or gas leaks out, the inflatable structure deflates and the radar reflector""s positioning to reflect radar waves is degraded. Therefore, past systems that include processes of affixing the radar reflector to the inflatable structure that require puncturing the surfaces of the inflatable structure are inherently disadvantageous.
Still another disadvantage of past inflatable structures with a radar reflector disposed therein has been that there is no method for a user to easily adjust the position of the radar reflector within the inflatable structure when the structure is inflated. As discussed previously, past radar reflector apparatus have been manufactured so that the apparatus may be folded or otherwise compacted for storage or transportation using a minimum of storage space. The radar reflector of past apparatus is typically permanently attached to the inner surface of the inflatable structure during manufacture. Due to the rigors of prolonged storage, the inflatable structure may not inflate to its intended symmetrical shape when it is inflated. Instead, the inflatable structure may inflate asymmetrically. Consequently, the radar reflector, which depends on such symmetrical inflation to optimally position it within the inflatable structure is not properly positioned within the non-uniform, inflated structure. Past radar reflector apparatus typically lack a convenient method for the user to manually adjust the position of the radar reflector within the inflatable structure after the structure has been inflated.
Yet another disadvantage of past inflatable structures with a radar reflector apparatus disposed therein has been that the shape of the inflatable structure is not conducive to securely positioning the radar reflector within the inflatable structure. Past apparatus typically use a spherical-shaped inflatable structure. While such a structure lends itself to uniform inflation, it does not provide any substantially planar surfaces upon which to affix the radar reflector within the structure. Consequently, the radar reflector is prone to being dislodged out of an optimal position to reflect radar waves when the apparatus is in use.
Information relevant to attempts to address these problems can be found in U.S. Pat. No. 2,463,517 (Chromak), U.S. Pat. No. 2,534,716 (Hudspeth et al.), U.S. Pat. No. 2,888,675 (Pratt et al.), U.S. Pat. No. 3,276,017 (Mullin), U.S. Pat. No. 4,673,934 (Gentry et al.) and U.S. Pat. No. 5,457,472 (Bjordal et al.). However, each one of these references suffers from one or more of the following disadvantages:
U.S. Pat. No. 2,463,517 (Chromak) does not disclose a means for a user to conveniently adjust the position of the radar reflector within the inflatable structure when the structure is inflated. Chromak also does not teach an inflatable structure having a plurality of planar surfaces.
U.S. Pat. No. 2,534,716 (Hudspeth et al.) does not disclose a means for a user to conveniently adjust the position of the radar reflector within the inflatable structure when the structure is inflated. Hudspeth also does not teach a means to effectively isolate the radar reflector supported within the inflatable structure from the effect of environmental forces imparted to the outer surface of the inflatable structure.
U.S. Pat. No. 2,888,675 (Pratt et al.) does not teach an inflatable structure having a plurality of planar surfaces. Further, Pratt does not disclose a means for a user to conveniently adjust the position of the radar reflector within the inflatable structure when the structure is inflated. Pratt also does not teach a means to effectively isolate the radar reflector supported within the inflatable structure from effect of environmental forces imparted to the outer surface of the inflatable structure.
U.S. Pat. No. 3,276,017 (Mullin) does not disclose a means for overcoming asymmetric inflation of the inflatable structure. In addition, Mullin does not teach a means for adjusting of the positioning of the corner reflector support members without disassembling the entire apparatus. Further, because the support members of Mullin are permanently attached to the inner surface of the inflatable structure, there is a risk that the corner reflector could tear the inflatable structure, thus degrading the utility of the apparatus as a radar reflector.
U.S. Pat. No. 4,673,934 (Gentry et al.) does not teach an inflatable structure having a plurality of planar surfaces. Further, Gentry does not disclose a means for a user to conveniently adjust the position of the radar reflector within the inflatable structure when the structure is inflated.
U.S. Pat. No. 5,457,472 (Bjordal et al.) does not teach an inflatable structure having a plurality of planar surfaces. Further, Bjordal does not disclose a means for a user to easily adjust the position of the radar reflector within the inflatable structure when the structure is inflated.
In contrast, the invention disclosed herein overcomes these disadvantages by using a polyhedral-shaped inflatable structure having a plurality of planar faces. A radar reflector is positioned and supported within the inflatable structure using means that effectively isolate the radar reflector from the effect of environmental forces upon the support members of the radar reflector when the invention is in use. The radar reflector disclosed by this invention is positioned and supported within the inflatable structure without necessity to resort to puncturing the inflatable structure in any manner. The present invention discloses a convenient process for fastening the radar reflector to the inflatable structure, whereby a user may expeditiously adjust the position of the radar reflector within the inflatable structure while the structure is inflated.
For the foregoing reasons, there is a need for an apparatus and process for reflecting radar waves wherein the apparatus uses a radar reflector that is supported and positioned with an inflatable structure so as to effectively isolate the radar reflector from the effects of environmental forces on the inflatable structure when the structure is inflated.
Also for the foregoing reasons, there is a need for an apparatus and process for reflecting radar waves wherein a radar reflector, disposed within an inflatable structure, may be conveniently repositioned within an inflatable structure while the inflatable structure is inflated.
The present invention is directed to an apparatus and process that satisfies the need for a radar reflector that is positioned land supported within an inflatable structure so as to effectively isolate the radar reflector from the effects of environmental forces on the inflatable structure when the structure is inflated. The present invention is further directed to an apparatus and process wherein a radar reflector, disposed within an inflatable structure, may be conveniently unfastened, repositioned, and refastened to the inner surface of the inflatable structure while the inflatable structure is inflated.
Therefore, an object of the present invention is to disclose a means of positioning and supported a radar reflector within an inflatable structure so that the radar reflector is effectively isolated from the effects of environmental forces on the inflatable structure when the structure is inflated.
Another object of the present invention is to disclose a means for a user to conveniently unfasten, reposition, and refasten a radar reflector within an inflatable structure when the structure is inflated.
A still further object of the present invention is to provide a means for positioning and supporting a radar reflector within an inflatable structure without puncturing the surfaces of the inflatable structure.
One other object of the present invention is to disclose an apparatus for reflecting radar waves wherein a polyhedral-shaped inflatable structure having a plurality of planar surfaces is used to support and position a radar reflector therein.
An object of the present invention is to provide a low-cost apparatus for reflecting radar waves, wherein the apparatus is lightweight and compact when not inflated.
Yet another object of the present invention is to provide an apparatus for reflecting radar waves wherein the inflatable structure is operable to rotate about an axis in response to environmental forces impinging upon the structure, and thereby causing the radar cross-section of the apparatus to fluctuate.
An apparatus for reflecting radar waves, in accord with the present invention, comprises an inflatable structure that has a substantially continuous inner flexible surface and an outer flexible surface so that the inflatable structure may be inflated with air, gas or lighter-than-air gas. At least one radar reflector is disposed within the inflatable structure. Support members are coupled to the radar reflector to support the radar reflector within the inflatable structure. The support members are disposed adjacent to the inner flexible surface so that the support members cooperate to position the radar reflector to reflect radar waves when the inflatable structure is inflated. Fasteners are disposed adjacent to the outer flexible surface of the inflatable structure, and the fasteners may be placed concentrically proximate about the support members to thereby fasten the radar reflector to the inflatable structure.
Preferably, each of the support members comprises a base member pivotally connected by a hinge to a fastening member so that the fastening member is pivotally disposed adjacent to the inner flexible surface of the inflatable structure when the inflatable structure is inflated.
In accord with one aspect of the present invention, each of the fasteners includes an annular band of elastomeric material.
As another aspect, the fasteners are disposed concentrically proximate about the fastening members so that the radar reflector is fastened to the inner surface of the inflatable structure.
In accord with another aspect of the present invention, the inflatable structure may be polyhedral-shaped, with a plurality of planar faces when the inflatable structure is inflated.
One other aspect of the present invention is that the inflatable structure may be cube-shaped, with six planar faces when the inflatable structure is inflated.
Another aspect of the present invention is that the radar reflector may comprise a corner reflector made of metallized plastic film and attached to a plurality of support filaments. The support filaments are attached to the support members.
Still another aspect of the present invention may include eight corner reflectors, conterminously connected together within the inflatable structure.
An apparatus for reflecting radar waves, in accord with the present invention, comprises a polyhedral-shaped inflatable structure that has a substantially continuous inner flexible surface and an outer flexible surface so that said inflatable structure may be inflated with air, gas or lighter-than-air gas. A radar reflector is disposed within the polyhedral-shaped inflatable structure. The radar reflector comprises eight conterminous corner reflectors of metallized reflective plastic film attached to a plurality of support filaments. Six support members adjustably couple the radar reflector to the inner flexible surface of the inflatable structure. Each fastening member further comprises a base member attached to the support filaments at a first end and pivotally connected by a hinge to a fastening member at a second end so that said radar reflector is positioned to reflect radar waves when the inflatable structure is inflated. Six fasteners are disposed adjacent to the outer flexible surface of the polyhedral inflatable structure. Each of the fasteners may be adjustably disposed concentrically proximate about each of the fastening members so that said radar reflector is thereby fastened to the inner surface of the inflatable structure when the inflatable structure is inflated.
A process for reflecting radar waves, in accord with the present invention, comprises positioning at least one radar reflector within an inflatable structure, fastening the radar reflector to the inner flexible surface of the inflatable structure, and repositioning the radar reflector within the inflatable structure so that that position of the radar reflector within the inflatable structure may be adjusted without deflating the inflatable structure.
Preferably, the act of positioning the radar reflector includes supporting the radar reflector within the inflatable structure by a plurality of support filaments.
In accord with another aspect of the present invention, fastening the radar reflector to the inflatable structure includes pivotally disposing the radar reflector adjacent to an inner surface of the inflatable structure.
Also preferably, the act of adjusting the radar reflector includes unfastening fasteners, disposed adjacent to an outer surface of the inflatable structure and concentrically proximate about support members of the radar reflector, repositioning the radar reflector within the inflatable structure, and refastening the fasteners adjacent to the outer surface and concentrically proximate to the radar reflector so that said reflector is thereby refastened to the inner flexible surface of the inflatable structure.
The apparatus and process of the present invention, using a radar reflector positioned and supported within an inflatable structure by pivotable support members disposed adjacent to the inner flexible surface of said structure, thus effectively isolate the radar reflector from environmental forces impinging upon the inflatable structure when the invention is in use. The disclosed apparatus and process of the present invention further permits convenient unfastening, repositioning, and refastening of the radar reflector within the inflatable structure without requiring the inflatable structure to be deflated.